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Our Odd Solar System

As of this month, we’ve discovered 884 planets, 692 planetary systems, 132 of them with more than one planet and, strange to tell, almost none of them look like us.

“We are now beginning to understand that nature seems to overwhelmingly prefer [planetary] systems that have multiple planets with orbits of less than 100 days,” says Steve Vogt, astronomer at the University of California, Santa Cruz. “This is quite unlike our own solar system, where there is nothing with an orbit inside that of Mercury. So our solar system is, in some sense, a bit of a freak and not the most typical kind of system that Nature cooks up.” …

As the discoveries roll in, Mike [Brown, an astronomer at Caltech,] is getting more and more uncomfortable. Though it will take a while to discover smaller planets, right now there’s only one planetary system that looks a lot like our own, he says. “HD 13931 b is nearly perfect. What I would desperately like to know is whether or not it has the small rocky bodies on the inside too. But it’ll be a long time before we can find that.”

Meantime, he is trying to get used to the idea that we live on an unusual planet in an unusual solar system. That’s two “unusuals.” One more than he’s used to. To live doubly-unusual, is to be luckier — and perhaps rarer — than we knew.

“It really is something that I find deeply weird,” he writes. “What does it all mean? I don’t know. I am certain that this single-minded emphasis on planets-in-habitable-zones is making people forget that there is still a lot of weird stuff happening out there and that we still don’t even understand the basics of how we ourselves got here.”